Crevice corrosion is a complex phenomenon which can affect stainless steels and certain other materials. The occurrence and ultimate extent of corrosion damage which may develop is highly dependent on a number of inter-related factors. Alloy composition, material surface finish, crevice geometry, bulk environment chemistry, and temperature are but a few of the variables which may influence resistance to crevice corrosion. This paper focuses on the crevice corrosion resistance of duplex stainless steels as determined in a number of varied test programs comprising exposure to natural seawater and other chloride containing waters. Data from several earlier published papers and previously unreported test results are analysed to better characterise the performance of this class of materials when subjected to a variety of conditions, including some that are representative of those found in a particular type of service. Both alloy tubular and sheet products have been tested with a variety of crevice forming devices, but mostly those described elsewhere as Perspex Crevice Assemblies (PCAs), and vinyl sleeves (plastic tubing). Some testing also involved the use of multiple crevice assemblies (MCAs) made of acetyl resin, and others in metal-to-metal crevice configurations.